Agreement between psychophysical tuning curves and the threshold equalizing noise test in dead region identification.

OBJECTIVE: Identification of dead regions is currently based on the results of psychophysical tuning curves (PTC) and the threshold equalizing noise (TEN) test. Summers et al (2003) found poor agreement (56%) between PTC- and TEN test results. Kluk and Moore (2005) argued that these results are explained by beat- and/or combination tone detection. The purpose of this study was to examine the diagnostic dead region relationship between PTCs, modified for beats and/or combination tone detection, and the TEN test with levels calibrated in hearing levels (HL), i.e., TEN[HL].

DESIGN: Twenty-four hearing-impaired ears were evaluated using PTCs and the TEN[HL] test.

RESULTS: The results show an agreement of about 75%, depending on the criteria applied, between PTC and the TEN[HL] test. Results also show that PTC probe levels affected diagnostic results in PTCs.

CONCLUSIONS: Recommended criteria based on the highest agreement score included a PTC shift of 20% and an 8-dB probe elevation above TEN masking levels for the TEN[HL] test. Low agreement scores and level dependent effects in PTCs and the TEN[HL] test suggest that identification of dead regions using a single test is not reliable.